RHEOLOGICAL CHARACTERISTICS OF A LIQUID WOOD-POLYMER COMPOSITE FOR THE PRODUCING OF DETAILS BY LAYER-BY-LAYER MOLDING

The article presents studies of rheological characteristics of a liquid wood-polymer composite material included wood flour (as part of a pine particle), epoxy resin with a hardener. Viscosity measurements were carried out using a rotary viscometer at various concentrations of the solid phase in the composite material. The relationship between the shear stress and the shear rate gradient is established. The analysis of rheological characteristics showed that the composite material exhibits both Newtonian and non-Newtonian properties of the liquid at concentrations below 30%, at a temperature of 20 °C. The boundaries of the transition to the lowest Newtonian viscosity are established and the yield limits at concentrations of the solid phase exceeding 20% are determined. The obtained rheological characteristics can be used to calculate the extruder feed channels in 3D printers, in order to prevent their clogging, when applying the composite in liquid form in layers.